Technical Field
The present invention relates to a power converter, and in particular to a three-port converter.
Description of Related Art
A solar battery-storage battery direct-current power system generally takes solar energy as an input source, with a storage battery as a backup power source to supply power to a load jointly. Since the power of the input source, the storage battery, and the load needs to be managed simultaneously, two or more converters are generally required to fulfill a system power management task jointly. All the converters are controlled in a distributed manner, the system is large in size and heavy in weight, and multi-stage power conversion exists, leading to lower system efficiency. In the prior art as shown in FIG. 1, a three-port converter is typically used to substitute a plurality of independent converters to implement the system power management, discrete magnetic elements are used to enable energy flow through the three ports, thereby realizing product application, and the prior art is characterized in that all the ports are mutually isolated through a transformer winding, but it has the following problems and shortcomings:
1) an independent magnetic-ring inductor is used, the coupling driving of a transformer is included for a high-side MOS transistor, and magnetic integration technology is not used so that many magnetic elements are present;
2) each port has larger input and output ripples, there are also many filter capacitors, and with more devices and large size and weight, more space is occupied and the power density is reduced; and
3) the isolation driving of the transformer is insufficient for the switching control of a switching tube.